As publicly known, the conventional lock or the locking device can be open by only one key. Also, it is designed in such a manner that after the lock is open or locked by the key, the key can be pulled out from the lock.
Thus, in the case of the locking device used publicly, for example, the locking device used for a locker in a subway station or a public bath, the manager had to manage the key one by one in order to prevent the key from being taken away by the user. Currently, in order to resolve such problem, at the time of using the locker, the locking device is designed in such a manner that the user cannot pull out the key while the locker is open.
However, both cases have problems in that the locker cannot be used if the user takes away the key at the locking state, and the lock has to be renewed or repaired. In particular, in the case that the user cannot pull out the key when the locker is open, it was difficult to manage the key since the key should always be inserted into the lock of the locker.
Meanwhile, the above locking device is used when the department store, the big supermarket or an amusement hall provide a predetermined key with a winner who wins a free gift so the winner opens the door of the gift box with the predetermined key to take the free gift. However, if the winner can pull out the key from the gift box after opening the lock of the box, the key could be missing. However, if the key cannot be pulled out, there still exists a problem that the manager needs to manage the key one by one for the next use.